221656306545 has 32 divisors (see below), whose sum is σ = 394090790400. Its totient is φ = 118206156672.

The previous prime is 221656306517. The next prime is 221656306579. The reversal of 221656306545 is 545603656122.

221656306545 is a `hidden beast` number, since 2 + 2 + 1 + 6 + 5 + 630 + 6 + 5 + 4 + 5 = 666.

It is not a de Polignac number, because 221656306545 - 2⁵ = 221656306513 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 221656306545.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1585189 + ... + 1719341.

It is an arithmetic number, because the mean of its divisors is an integer number (12315337200).

Almost surely, 2^221656306545 is an apocalyptic number.

It is an amenable number.

221656306545 is a deficient number, since it is larger than the sum of its proper divisors (172434483855).

221656306545 is a wasteful number, since it uses less digits than its factorization.

221656306545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146406 (or 146400 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 221656306545 in words is "two hundred twenty-one billion, six hundred fifty-six million, three hundred six thousand, five hundred forty-five".